| Based on the analysis of the metallogenic geological setting, characteristic of Gaolong-Badu gold ore belt and typical gold ore deposit, geochemistry characteristic of ore deposit and characteristic of remote-sensing geology, this article utilized MapGIS software platform to set up geo-spatial database and extracted various of ore-searching information, set up geology and remote-sensing integrated information metallogenic prognosis model, estimated quantitatively the gold mineral resource of Gaolong-Badu gold ore belt. Ⅰ. Regional metallogenic geologic settingThe evolution of Youjiang basin may be divided into four stages: passive continental margin rift stage(from Mid-Devonian to Lower-Pennsylvanian:D2-P1), back-arc basin stage(from Mid-Pennsylvanian to Lower-Triassic:P2-T1), Depressed-basin stage(from Mid-Triassic to Lower-Triassic:T2-T3) and continental fold stage(T3). The article analyzed the relationship between the evolution of Youjiang basin and gold mineralization, summed up the regional ore-searching evidence, pointed out that there are three favorable formation in region(formation of Devonian, formation of Lower-Pennsylvanian and formation of Upper or Mid-Triassic), that the lithofaeies belt, micro-lithofacies belt and lithofacies intermediate belt control the distribution of gold ore deposits, that the distribution of gold ore deposits(points) are controlled by the dome and anticline structure, and that the gold ore belt is controlled by the regional faults and that the location of ore deposits(bodies) are controlled by sub-level faults.Ⅱ. Geology of ore belt and Gaolong gold ore depositThe article analyzed the geologic characteristic of ore belt and Gaolong gold ore deposit. Summed up the ore-controlling factors and ore-searching indicator of ore belt. And pointed out the distribution of ore bodies of Gaolong gold ore deposit is controlled by formation, lithologic character and fault mainly.Ⅲ. GeochemistryResearch on the geochemistry of strata and ore indicates that associated element of gold ore deposit, Such as Ag, As, Sb, Hg, are related with the gold abundance.Research on the geochemistry of REE indicates that the distribution of REE of strata and ore has similar distribution model, as is to say that the part of ore-forming substance drive from the strata.Research on the sulfur and lead isotopes of ore deposit indicates that, δ 34S ranges from-15.27 to +32.29‰, 206Pb/204Pb ranges from 18.270 to 18.7003 , 207Pb/204Pb ranges from 15.62 to 15.7667, 208Pb/204Pb ranges from 38.2667 to 39.0513, the model-lead age is 160~301Ma, ore-forming has a multi-source and multi-stage.Research on the mineral fluid inclusion shows that the metallogenic temperature ranges from 100℃ to 340℃ mainly.Ⅳ. Remote-sensing geologyUtilized digital image processing methods to process the ETM data , the result is better, extracted alteration information and strengthened edge of the liner-annular structure. The gold ore deposit is located in the joint part and tangent part of line-ring and the edge of the ring structure. A large amount of quantitative information has obtained by using MORPAS software.Ⅴ. Based on GIS mineral resource assessmentVarious of mineralization information is extracted by using spatial analyses of MAPGIS platform. A geological assessment model was built, there are 15 assessment variable in the model. The ore-searching information of every variable is calculated by using "condition probability method", the information of every unit is calculated. With certain information value(1.7), five ore-searching area is drew: A1(Gaolong ore-searching area),A2(Badu ore-searching area),B1(Pingle-Nagu ore-searching area),B2(Weirong ore-searching area)andB3(Yuanle ore-searching area).According to the quantitative theory, the article analyzed the relationship between information amount and mineral resource of the model unit extracted, set up the regression analysis model between information amount and mineral resource, and predict the potential gold mineral resource, the total gold resource is 30.384t as assessment result. |
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